Method of manufacturing stamping or printing dies or plates or blocks.



- pecially because paper,

foundations become carbonized thereby.

UNITED STATES PATENT OFFICE.

J'OSEF RICHTER, OF GENEVA, SWITZERLAND.

METHOD OF MANUFACTURING STAMPING b3 PRINTING DIES OR PLATES OR BLOCKS.

No Drawing.

T 0 all whom it may concern Be it known that I, Josnr RICHTER, subject of the Republic of Switzerland, resid- 1ng at 3 Quai du Montblanc, Geneva, Switzerland, have invented certain new and useful Improvements in Improved Methods of Manufacturing Stamping or Printing Dies or Plates or Blocks, of which the following is a specification.

The present invention relates to an improved method of manufacturing, stamping or printing dies or plates or blocks- It has been proposed to use celluloid for this purpose. but such plates or blocks are too hard at the edges and wear off too easily. Further, they do not properly fit to the surface onto which they are applied, and on the slightest superheating, which is generally unavoidable, blisters are formed. Attempts have also been made to employ acetyl cellulose. This was obtained from solutions in acetic ether, chloroform or acetone, but sheets of sufficient thickness for making deep impressions can not be obtained, even if non-drying oils and phenol derivatives are added to the solutions. These oils cause blisters and the masses obtained from the solutions are sticky.

Further, these masses only soften at a high temperature, and it is therefore necessar to heat them to 120 150 centigrade. t these temperatures the acetyl cellulose decomposes and it is :difficult to handle the hot sheets, more esfabrics, or other According to the present invention the above disadvantages are obviated by employing masses which consist of acetyl-cellulose preferably soluble in acetone, prepared in various ways to yield a suitable product, such as by treatment of acetonesoluble ac'etyl cellulose with mixtures of non-solvents or of solvents and non-solvents, with or without the addition of camphor or camphor substitutes, and filling materials. Or acetone-soluble acetyl cellulose may be treated with camphor or camphor substitutes in quantities not suflicient for dissolving the acetyl cellulose. The above known methods of preparing such masses are not clai ed. The invention is concerned with the production from them of printingplates, which is rendered possible by their special properties,- i. 0., their hardness when cold their low melting point, and their ca- -"'pacity of yielding a sharp impression when Patented Mar. 16, 1915.

Application flied my 29, 1911. Serial No. 630,114.

heated even up to the melting point. The process is describedmore fully below. It essentially consists in heating the material above the softening point before making the impression. For example, these masses are produced from acetone-soluble acetyl cellulose Which has been treated with camphor or camphor substitutes and cut into blocks or mechanically rolled. These masses are distinguished by their extreme hardness and exceedingly low softening point. Their melting point is even lower than that of celluloid as they melt or soften at about 70 centigrade. Now, the surprising fact has been discovered that if sheets of this material, which can be obtained in any desired thickness of 23 millimeters and more are brought quite to the melting point, good printing blocks can be produced, although partial decomposition takes place with the formation of blisters. It is on this remarkable property that the invention depends. The material is heated over 50 and up to 100 centigrade, when it becomes highly softened. WVhen the male counterparts are pressed into the matrix, the blisters absolutely disappear under the pressure, the surface becomes perfectly smooth, and the details of the design appear in extraordinary fineness, and in a surprising shading off of the middle tones. These effects can not e obtained with celluloid or with the masses obtained from solutions of acetyl cellulose in ether, chloroform or acetone.

This process is also applicable ,in making printing blocks of objects such as lace, fabrics, relief designs and the like. These objects can be readily pressed into the highly softened, hot material, thus producing a block which is equal to those made by the expensive way of engraving, etching or wood-carving. Beliefs and printing blocks can then be roduced in any desired number by pressing the ,perfectly cold matrix against a very hot softened sheet of the material, when the two parts can be taken apart a very short time after effecting the impression without damage. It is remarkable that this result is obtained even though the sheets are not necessarily different in composition and can have exactly the same melting point. A material can be used in which filling materials, such as mica and other suitable substances, are added to the acetyl cellulose mass in quantities of from molded themselves or the like can be pressed into such material, thus forming a matrix from which as many counterparts can be molded as desired: even if the same material is used for the male counterpart and the matrix, these do not stick together as is the case with celluloid.

It is a very important advantage of the present invention that no shrinkage or variation of dimensions occurs b the evaporation of solvents, which is 0% special importance for multicolor printing. The dies, blocks or plates are very cheap as com: pared with metal printing blocks, they can be quickly produced, are impervious to shocks or mechanical damages during trans port, and are not affected by atmospheric influences. They serve for replacing metal printing blocks or rollers, steel engravings, zinc clichs, sets of stereotypes, as well as cardboard and powder matrices. The printing surfaces are also very suitable for rotary printing, as they easily attach themselves to the cylinder and the like.

What I claim as new and desire to secure by Letters Patent is 1. A method of making a printing plate consisting in forming from acetyl oellulose soluble in acetone and camphor substitutes a hard solid body or mass having very slight plasticity, said acetone and camphor substitutes being used in quantities not sufficient for dissolving the acetyl cellulose, the materials and proportions being specially selected so as to give a body having a softening point of over 60 and below 100 0., then heating the said hard solid body to a point above the point at which it becomes plastic and nearly to the point at which it is made pasty by said heating, and while so heated forming it into a printing plate.

2. A method of making a printing plate consisting in forming from acetyl cellulose soluble in acetone and camphor substitutes a hard solid body or mass having very slight plasticity, said acetone and camphor substitutes being used in quantities not suflicient for dissolving the acetyl cellulose, the materials and proportions being specially selected, together with the addition of more 3. A method of making a printing plate consisting in forming from acetyl cellulose soluble in acetone and camphor substitutes a hard solid body or mass having very slight plasticity, said acetone and camphor substitutes being used in quantities not sulficient for dissolving the acetyl cellulose, the materials and proportions being specially selected so as to give a body having a softening point of over and below 100 0.,'

then heating said hard solid body or mass to a point above the point at which it becomes plastic and nearly to the point at which it is made pasty by said heating and while so heated subjecting it to pressure against an object adapted to mold it into the desired form. I

4. A method of making a printing plate consisting in forming from acetyl cellulose soluble in acetone and camphor substitutes a hard solid body or mass having very slight plasticity, said acetone and camphor substitutes being used in quantities notsuflicient for dissolving the acetyl cellulose, the materials and proportions being specially selected, together with the addition of more than 50 per cent. of filling materials, so as to give a body having a softening point of over 60 or below 100 0., then heating said hard solid body or mass to a point above the point at which it becomes plastic and nearly to the point at which it is made pasty by said heating and while so heated subjecting it to pressure a ainst an object I to mold it into the desired orm.

In testimony whereof I afiix my signature in presence of two Witnesses.

J OSEF RICHTER.

Witnesses E. Lo'r'rl T. STRAUSS. 

